1. Field of the Invention
This invention relates to a rotor for a magnetogenerator and a process of manufacturing the same, and more particularly to improvements in a construction for joining a yoke to a boss member. The invention is effectively utilized in manufacturing a rotor in a magnetogenerator for small-sized vehicles including motorcycles, outboard motors or portable generators.
2. Related Art Statement
In general, a magnetogenerator comprises: a rotor, in which a plurality of magnets are provided at regular intervals on the inner peripheral surface of a generally bowl-shaped yoke; and an armature, in which a plurality of coil units are provided at regular intervals in yoke of the rotor; wherein the armature is fixed to an outer shell of an engine, and the rotor is coupled onto a rotary shaft of the engine.
The magnetogenerator of the type described is constructed such that, in the rotor, the boss member thereof coaxially connected to the bottom wall of the yoke is fixed to the rotary shaft of the engine, whereby the rotor is linked with the engine. An example of the construction for coaxially connecting the boss member to the bottom wall of the yoke, is a rotor in a magnetogenerator described in Japanese Utility Model Laid-Open No. 60-11662, for example.
More specifically, as shown in FIG. 6, in the rotor of this magnetogenerator, a boss member 1 protruding thereon is provided with a small-diameter flange 2, and a serration 3 is formed at one side of the flange 2. The boss member 1 is coupled such that the boss member can be serration-jointed to an opening 5 of the yoke 4 and the flange 2 can be in abutting contact with the brim, or lip, around the opening 5. Further, a clinched finished portion 6 is formed at the other end of the flange 2 of the serration 3 of the boss member 1 such that the finished portion 6 can clamp the brim around the opening 5 of the yoke 4 between the portion 6 and the flange 2, thus fixedly joining the boss member 1 to the yoke 4.
With the rotor in the magnetogenerator having the above-described construction, since the flange 2 protrudes to the outside from the bottom wall of the yoke 4, there are presented the disadvantages that the size of the rotor in the axial direction is increased and it is difficult to increase the mechanical strength of the rotor against torque.